From Aristotle to Newton: A Revolution in Science

1. From Aristotle to Newton:A Revolution in Science

2. Setting the Scene: Philosophy of the Time • The heavens represent perfection. • The heavens are immutable. • The circle is the perfect shape. • All heavenly motions must be circular. • The earth is at the center of the universe. • These ideas originated with Aristotle.

3. “The astronomer must try his utmost to explain celestial motions by the simplest possible hypothesis; but if he fails to do so, he must choose whatever other hypotheses meet the case.” -Ptolemy of Alexandria (140 A.D.)

4. Wanderers in the Heavens East South West • Planets don’t maintain a fixed position in the sky. • Their brightness varies depending on how far away they are from Earth at any time. • Planets appear to speed up and slow down in their motion. • Planets also appear at times to move backwards, which is known as retrograde motion (normal motion is to move west to east across celestial sphere).

5. Ptolemy tried to crate a model that would account for retrograde motion.He placed the planets in orbits (deferents) on orbits (epicycles) all around the Earth. Epicycle Deferent Earth

6. Ptolemy’s Epicycles

7. Ptolemy’s Epicycles

8. Ptolemy’s Epicycles

9. Ptolemy’s Epicycles

10. Ptolemy’s Epicycles

11. Ptolemy’s Epicycles

12. Ptolemy’s Epicycles

13. Ptolemy’s Epicycles

14. Ptolemy’s Epicycles

15. Ptolemy’s Epicycles

16. Ptolemy’s Epicycles

17. Ptolemy’s Epicycles

18. Ptolemy’s Epicycles

19. Ptolemy’s Epicycles

20. Ptolemy’s Epicycles

21. Ptolemy’s Epicycles

22. Ptolemy’s Epicycles

23. Ptolemy’s Epicycles

24. Ptolemy’s Epicycles

25. Ptolemy’s Epicycles

26. Ptolemy’s Epicycles

27. Ptolemy’s Epicycles

28. Ptolemy’s Epicycles

29. Ptolemy’s Epicycles Where is retrograde motion occurring? Planet’s Path

30. Ptolemy’s Epicycles Where is retrograde motion? Planet’s Path Planet’s Path

31. On the Ptolemaic system: • “A system of this sort seemed neither sufficiently absolute nor sufficiently pleasing to the mind.” • --Copernicus

32. Why heliocentric NOW??? • Renaissance: • art • literature • medicine • exploration

33. Copernicus (1473 – 1543 AD) is known for : • First observations of the sun • First sun centered model of the solar system or universe • The world’s best naked-eye astronomical observations in history • Creating first a theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

34. Copernicus (1473 – 1543 AD) is known for - • First observations of the sun • First sun centered model of the solar system or universe • The world’s best naked-eye astronomical observations in history • Creating first theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

35. Copernicus (1473 – 1543 AD) - • Probably died a virgin • Was a priest and Lawyer • Had artificial wooden and silver noses • Probably died of Mercury poising • Rumored to have died of a bladder burst • Was blind at the time of his death • Was labeled a heretic by the church

36. Copernicus (1473 – 1543 AD) - • Probably died a virgin • Was a priest and Lawyer • Had artificial wooden and silver noses • Probably died of Mercury poising • Rumored to have died of a bladder burst • Was blind at the time of his death • Was labeled a heretic by the church

37. Retrograde motion is an apparent motion caused when one planet moves from being behind another planet to being in front of the other planet. Copernicus devised the first comprehensive heliocentric cosmogony to successfully explain retrograde motion

38. “To demonstrate that the appearances are saved by assuming the Sun at the center and the Earth in the heavens is not the same thing as to demonstrate that in fact the Sun is in the center and the Earth in the heavens. I believe that the first demonstration may exist, but I have grave doubts about the second.” • --Cardinal Bellarmine • (1615)

39. Tycho Brahe (1546-1601) - • Probably died a virgin • Was a priest and Lawyer • Had artificial wooden and silver noses • Probably died of Mercury poising • Rumored to have died when his bladder burst • Was blind at the time of his death • Was labeled a heretic by the church

40. Tycho Brahe (1546-1601)- • Probably died a virgin • Was a priest and Lawyer • Had artificial wooden and silver noses • Probably died of Mercury poising • Rumored to have died when his bladder burst • Was blind at the time of his death • Was labeled a heretic by the church

41. Tycho Brahe (1546-1601) is known for - • First telescope observations of the sun • First sun centered scientific model of the solar system or universe • Being the world’s best naked-eye astronomer • Creating first theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

42. Tycho Brahe (1546-1601) is known for - • First telescope observations of the sun • First sun centered scientific model of the solar system or universe • Being the world’s best naked-eye astronomer • Creating first theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

43. Tycho Brahe measured distances using parallax that disproved ancient ideas about the heavens • He observed a supernova in 1572 and with this showed that the heavens were both changing and had a dimension of distance; this troubled scholars who previously thought the heavens were unchanging. • He showed that comets were objects that occurred in the region of the planets, not in Earth’s atmosphere.

44. Johannes Kepler 1571 - 1630 - • Probably died a virgin • Was a priest and Lawyer • Had artificial wooden and silver noses • Probably died of Mercury poising • Rumored to have died when his bladder burst • Was blind at the time of his death • Was labeled a heretic by the church

45. Johannes Kepler 1571 - 1630 - • None of these. • He was a deeply religious man and a family man. • He was rumored to have hated Tycho Brahe and was in the relationship for the data. With that data he changed the understanding of motion of heavenly bodies forever. • He was also a writer, who wrote children stories about the heavens.

46. Johannes Kepler 1571 - 1630is Known for - • First telescope observations of the sun • First sun centered scientific model of the solar system or universe • Being the world’s best naked-eye astronomer • Creating first theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

47. Johannes Kepler 1571 - 1630 is Known for - • First telescope observations of the sun • First sun centered scientific model of the solar system or universe • Being the world’s best naked-eye astronomer • Creating first theoretical model to explain planetary motions • Creating first a theoretical model for explaining gravity

48. Kepler’s First Law: The orbit of a planet about the Sun is an ellipse with the Sun at one focus.

49. Eccentricity, e • how squashed or out of round the ellipse is • a number ranging from 0 for a circle to 1 for a straight line • e = 0.02 • e = 0.7 • e = 0.9

50. What is the shape of Earth’s orbit around the Sun? Earth, e = 0.016